Reduced White Matter Fiber Density in Autism Spectrum Disorder

Dimond, Dennis; Schuetze, Manuela; Smith, Robert E.; Dhollander, Thijs; Cho, Ivy; Vinette, Sarah A.; Eycke, Kayla Ten; Lebel, Catherine; McCrimmon, Adam W.; Dewey, Deborah; Connelly, Alan; Bray, Signe

doi:10.1093/cercor/bhy348

Cited by 78 publications

(83 citation statements)

References 40 publications

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“…FBA offers two major advantages over alternative dMRI analysis techniques: sensitivity to fibre properties (density and morphology), and specificity to fi bre populations within vo xels (or “ fixels” ). This combination of improved sensitivity and specificity increases the possibility of assigning group differences in fibre properties to specific fibre populations (Dimond et al, ; Gajamange et al, ; Genc et al, ; Mito et al, ).…”

Section: Introductionmentioning

confidence: 99%

Impact of b‐value on estimates of apparent fibre density

Genc

Tax

Raven

et al. 2020

Human Brain Mapping

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Recent advances in diffusion magnetic resonance imaging (dMRI) analysis techniques have improved our understanding of fibre‐specific variations in white matter microstructure. Increasingly, studies are adopting multi‐shell dMRI acquisitions to improve the robustness of dMRI‐based inferences. However, the impact of b‐value choice on the estimation of dMRI measures such as apparent fibre density (AFD) derived from spherical deconvolution is not known. Here, we investigate the impact of b‐value sampling scheme on estimates of AFD. First, we performed simulations to assess the correspondence between AFD and simulated intra‐axonal signal fraction across multiple b‐value sampling schemes. We then studied the impact of sampling scheme on the relationship between AFD and age in a developmental population (n = 78) aged 8–18 (mean = 12.4, SD = 2.9 years) using hierarchical clustering and whole brain fixel‐based analyses. Multi‐shell dMRI data were collected at 3.0T using ultra‐strong gradients (300 mT/m), using 6 diffusion‐weighted shells ranging from b = 0 to 6,000 s/mm2. Simulations revealed that the correspondence between estimated AFD and simulated intra‐axonal signal fraction was improved with high b‐value shells due to increased suppression of the extra‐axonal signal. These results were supported by in vivo data, as sensitivity to developmental age‐relationships was improved with increasing b‐value (b = 6,000 s/mm2, median R2 = .34; b = 4,000 s/mm2, median R2 = .29; b = 2,400 s/mm2, median R2 = .21; b = 1,200 s/mm2, median R2 = .17) in a tract‐specific fashion. Overall, estimates of AFD and age‐related microstructural development were better characterised at high diffusion‐weightings due to improved correspondence with intra‐axonal properties.

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Section: Introductionmentioning

confidence: 99%

Impact of b‐value on estimates of apparent fibre density

Genc

Tax

Raven

et al. 2020

Human Brain Mapping

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“…Myelination starts, on average, 28 weeks after conception and continues throughout adolescence and is responsible for increases in relative white matter volume and for water diffusion changes within white matter tracts (van Tilborg et al 2018), which can be examined using diffusion tensor imaging. Moreover, diffusion tensor images reveal information about the density of axonal fiber packing in the brain, another measure that is indicative of white matter integrity (Dimond et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Exposure to Air Pollution during Pregnancy and Childhood, and White Matter Microstructure in Preadolescents

Lubczyńska

Muetzel

Marroun

et al. 2020

Environ Health Perspect

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BACKGROUND: Air pollution has been related to brain structural alterations, but a relationship with white matter microstructure is unclear. OBJECTIVES: We assessed whether pregnancy and childhood exposures to air pollution are related to white matter microstructure in preadolescents. METHODS: We used data of 2,954 children from the Generation R Study, a population-based birth cohort from Rotterdam, Netherlands (2002-2006). Concentrations of 17 air pollutants including nitrogen oxides (NO X), particulate matter (PM), and components of PM were estimated at participants' homes during pregnancy and childhood using land-use regression models. Diffusion tensor images were obtained at child's 9-12 years of age, and fractional anisotropy (FA) and mean diffusivity (MD) were computed. We performed linear regressions adjusting for socioeconomic and lifestyle characteristics. Single-pollutant analyses were followed by multipollutant analyses using the Deletion/Substitution/Addition (DSA) algorithm. RESULTS: In the single-pollutant analyses, higher concentrations of several air pollutants during pregnancy or childhood were associated with significantly lower FA or higher MD (p < 0:05). In multipollutant models of pregnancy exposures selected by DSA, higher concentration of fine particles was associated with significantly lower FA [−0:71 (95% CI: −1:26, −0:16) per 5 lg=m 3 fine particles] and higher concentration of elemental silicon with significantly higher MD [0.06 (95% CI: 0.01, 0.11) per 100 ng=m 3 silicon]. Multipollutant models of childhood exposures selected by DSA indicated significant associations of NO X with FA [−0:14 (95% CI: −0:23, −0:04) per 20-lg=m 3 NO X increase], and of elemental zinc and the oxidative potential of PM with MD [0.03 (95% CI: 0.01, 0.04) per 10-ng=m 3 zinc increase and 0.07 (95% CI: 0.00, 0.44) per 1-nmol DTT=min=m 3 oxidative potential increase]. Mutually adjusted models of significant exposures during pregnancy and childhood indicated significant associations of silicon during pregnancy, and zinc during childhood, with MD. DISCUSSION: Exposure in pregnancy and childhood to air pollutants from tailpipe and non-tailpipe emissions were associated with lower FA and higher MD in white matter of preadolescents.

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“…Characterizing typical neurodevelopment in early childhood is important as it provides a comparative baseline for detecting abnormal brain development during a period of life which has been associated with the emergence of various neurodevelopmental and psychiatric disorders. Decreased axonal/neurite density has been found in school-aged children who were born very-preterm (VPT) (Kelly et al, 2016), as well as in youth with autism spectrum disorder (ASD) (Dimond et al, 2019b), and in adults with first-episode psychosis (Rae et al, 2017). These structural abnormalities have been associated with decreased IQ and visuomotor function in children born VPT (Kelly et al, 2016; Young et al, 2019), and greater symptoms of social impairment in individuals with ASD (Dimond 2019).…”

Section: Discussionmentioning

confidence: 99%

Maturation and interhemispheric asymmetry in neurite density and orientation dispersion in early childhood

Dimond

Heo

et al. 2019

Preprint

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BackgroundThe brain’s white matter undergoes profound changes during early childhood, which are believed to underlie the rapid development of cognitive and behavioral skills during this period. Neurite density, and complexity of axonal projections, have been shown to change across the life span, though changes during early childhood are poorly characterized. Here, we utilize neurite orientation dispersion and density imaging (NODDI) to investigate maturational changes in tract-wise neurite density index (NDI) and orientation dispersion index (ODI) during early childhood. Additionally, we assess hemispheric asymmetry of tract-wise NDI and ODI values, and longitudinal changes.MethodsTwo sets of diffusion weighted images (DWI) with different diffusion-weighting were collected from 125 typically developing children scanned at baseline (N=125; age range=4.14-7.29; F/M=73/52), 6-month (N=8; F/M=8/0), and 12-month (N=52; F/M=39/13) timepoints. NODDI and template-based tractography using constrained spherical deconvolution were utilized to calculate NDI and ODI values for major white matter tracts. Mixed-effects models controlling for sex, handedness, and in-scanner head motion were utilized to assess developmental changes in tract-wise NDI and ODI. Paired t-tests were used to assess interhemispheric differences in tract-wise NDI and ODI values and longitudinal changes in cross-sectional and 12-month longitudinal analyses, respectively.ResultsMaturational increases in NDI were seen in all major white matter tracts, though we did not observe the expected tract-wise pattern of maturational rates (e.g. fast commissural/projection and slow frontal/temporal tract change). ODI did not change significantly with age in any tract. We observed higher cross-sectional NDI and ODI values in the right as compared to the left hemisphere for most tracts, but no hemispheric asymmetry for longitudinal changes.ConclusionsThese findings suggest that neurite density, but not orientation dispersion, increases with age during early childhood. In relation to NDI growth trends reported in infancy and late-childhood, our results suggest that early childhood may be a transitional period for neurite density maturation wherein commissural/projection fibers are approaching maturity, maturation in long range association fibers is increasing, and changes in limbic/frontal fibers remain modest. Rightward asymmetry in NDI and ODI values, but not longitudinal changes, suggests that rightward asymmetry of neurite density and orientation dispersion is established prior to age 4.

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Reduced White Matter Fiber Density in Autism Spectrum Disorder

Cited by 78 publications

References 40 publications

Impact of b‐value on estimates of apparent fibre density

Impact of b‐value on estimates of apparent fibre density

Exposure to Air Pollution during Pregnancy and Childhood, and White Matter Microstructure in Preadolescents

Maturation and interhemispheric asymmetry in neurite density and orientation dispersion in early childhood

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